Internally finned tube

Claim 2

An internally finned tube for use as part of a heat-exchanging system comprising: an elongated cylindrical tube; an array of fins in the form of a hollow integral sheet metal cylinder having V-shaped corrugations, with the corrugation ridges extending parallel to the axis of the tube when said cylinder is inserted in the tube, the outer ridges of said cylinder being in contact with the inner surface of the wall of said tube for substantially the full length of said outer ridges, the cylinder being severed along most but not all of the length of each of said outer ridges, the severence lines severing the outer radial ends of each fin from each other to define narrow clean-cut edges longitudinally extending with sharp corners for contact with the inner surface of the tube wall said sharp edges defining therebetween a crevice area, one of either the cylinder or the inner surface of the tube wall being clad with a material having a melting point lower than that of either the base material of the tube or of the cylinder so that said sharp edges of the fins are brazed to the inner surface of the tube said sharp edges bonded into said cladding material, the unsevered portions maintaining said cylinder as an integral unit for insertion into the tube.

Claim 3

The tube of claim 1 wherein each fin is provided with longitudinally spaced openings to permit fluid to flow transversely through each fin from one side of each fin to the other.

Claim 4

The tube of claim 1 which further comprises separate resilient means located within said cylinder to bias said fins radially outwardly to maintain contact between said outer ridges and the inner surface of the tube wall.

Claim 5

An internally finned tube for use as part of a heat-exchanging system comprising: an elongated cylindrical tube; an array of fins in the form of a hollow integral sheet metal cylinder having V-shaped corrugations, with the corrugation ridges extending parallel to the axis of the tube when said cylinder is inserted in the tube, the outer ridges of said cylinder being in contact with the inner surface of the wall of said tube for substantially the full length of said outer ridges, each of said outer ridges being notched at a plurality of spaced locations along their length, each notch being formed by the removal of metal at said ridge and for a predetermined depth therefrom toward each adjacent inner ridge, said notches being arranged in relatively widely spaced pairs, each notch pair comprising two very closely spaced notches which define therebetween a very narrow readily yieldable connecting link of metal bridging the gap between the notches of said pair and across the outer ridge, said outer ridges between said notched pairs being slit in a longitudinal direction to completely sever the two sides of each ridge from each other except for said connecting links, such severence leaving a clean-cut edge on the outer radial end of each fin for engaging it with the inner surface of the tube wall, one of either the cylinder or the inner surface of the tube wall being clad with a material having a melting point lower than that of either the base material of the tube or of the cylinder so that said sharp edges of the fins may be brazed to the inner surface of the tube, said fins being so disposed within the tube that fluid flowing from the tube may be in contact with both faces of each fin as well as with the inner surface of the tube wall.

Claim 6

An internally finned tube for use as part of a heat-exchanging system comprising: an elongated cylindrical tube; an array of fins in the form of a hollow integral sheet metal cylinder having V-shaped corrugations, with the corrugation ridges extending parallel to the axis of the tube when said cylinder is inserted in the tube, the outer ridges of said cylinder being in contact with the inner surface of the wall of said tube for substantially the full length of said outer ridges, each of said outer ridges being notched at a plurality of spaced locations along their length, each notch being formed by the removal of metal at said ridge and for a predetermined depth therefrom toward each adjacent inner ridge, said notches being arranged in relatively widely spaced pairs, each notch pair comprising two very closely spaced notches which define therebetween a very narrow readily yieldable connecting link of metal bridging the gap between the notches of said pair and across the outer ridge, said outer ridges between said notched pairs being slit in a longitudinal direction to completely sever the two sides of each ridge from each other except for said connecting links, such severence leaving a clean-cut edge on the outer radial end of each fin for engaging it with the inner surface of the tube wall, one of either the cylinder or the inner surface of the tube wall being clad with a material having a melting point lower than that of either the base material of the tube or of the cylinder so that said sharp edges of the fins may be brazed to the inner surface of the tube, said fins being so disposed within the tube that fluid flowing from the tube may be in contact with both faces of each fin as well as with the inner surface of the tube wall.

Claim 7

The tube of claim 4 wherein each fin is provided with longitudinally spaced openings to permit fluid to flow transversely through each fin from one side of each fin to the other.

Claim 8

The tube of claim 4 which further comprises separate resilient means located within said cylinder to bias said fins radially outwardly to maintain contact between said outer ridges and the inner surface of the tube wall.